EFFECTS OF DIETARY PROPIONIC ACID ON SERUM LIPIDS AND LIPOPROTEINS OF PIGS FED DIETS SUPPLEMENTED WITH SOYBEAN MEAL OR CANOLA MEAL

Abstract

Sixty-four crossbred pigs averaging 24 kg liveweight at allotment were used to study the effects of dietary propionic acid (PA) on cholesterol metabolism. Isonitrogenous and isoenergetic diets were based on either barley-soybean meal or barley-canola meal and contained either 0, 3, 6 or 9% PA. Inclusion of PA significantly reduced the levels of total serum cholesterol, associated entirely with a reduction in the high density lipoprotein fraction. There was a slight increase in the lipid content of both hearts and livers due to PA inclusion; hearts showed slight elevations in triglycerides, and livers had slightly elevated cholesterol and phospholipid levels. Pigs fed diets supplemented with soybean meal had lower levels of serum calcium, higher serum urea nitrogen, lower total serum cholesterol, lower low density lipoprotein cholesterol and lower circulating triglycerides compared with those fed canola meal. Hearts from pigs fed soybean meal appeared to have higher levels of total lipid, indicated by increases in triglycerides and phospholipids. There were no differences in lipid composition of livers due to source of protein supplement.